[tem]树状数组

通过差分可以玩区间：

bi＝ai－a(i-1)

查询时考虑位置对答案的贡献 推导一下

 #include<iostream>
 #include<cstdio>
 #include<algorithm>
 #include<cstring>
 using namespace std;
 typedef long long ll;
 const int N=1e5;

 ll n,a[N],b[N],c1[N],c2[N];

 //basic
 inline int lowbit(int x){return x&-x;}
 ll sum(ll *c,int x){
     ll ret=;
     for(;x>;x-=lowbit(x)) ret+=c[x];
     return ret;
 }
 ll query(ll *c,int l,int r){
     return sum(c,r)-sum(c,l-);
 }
 void addPoint(ll *c,int x,ll v){
     for(;x<=n;x+=lowbit(x)) c[x]+=v;
 }
 void build(ll *c,ll *a,ll n){
     for(int i=;i<=n;i++){
         c[i]+=a[i];
         if(i+lowbit(i)<=n)
             c[i+lowbit(i)]+=c[i];   //!!c[i] or while
     }
 }

 //interval-interval
 void initB(ll *b,ll *a){
     b[]=a[];
     for(int i=;i<=n;i++) b[i]=a[i]-a[i-];
 }
 void addRange(int l,int r,ll v){
     addPoint(c1,l,v);        addPoint(c2,l,v*l);
     addPoint(c1,r+,-v);    addPoint(c2,r+,-v*(r+));
 }
 ll sumRange(int l,int r){
     return query(c1,,l)*(r-l+)+ query(c1,l+,r)*(r+) -query(c2,l+,r);
 }

 int t,l,r;
 ll v;
 int main(){

     //freopen("in.txt","r",stdin);
     //freopen("1.txt","w",stdout);

     cin>>n>>t;
     for(int i=;i<=n;i++) cin>>a[i];
 //    for(int i=1;i<=n;i++){
 //        addRange(i,i,a[i]);
 //    }

     initB(b,a);
     build(c1,b,n);
     for(int i=;i<=n;i++) b[i]*=i;
     build(c2,b,n);

     while(t--){
         int flag;
         cin>>flag;
         if(flag==){
             cin>>l>>r;
             cout<<sumRange(l,r)<<"\n";
         }else{
             cin>>l>>r>>v;
             addRange(l,r,v);
             cout<<sumRange(l,r)<<"\n";
         }
     }
 }